Because the one to three grand for a billboard couldn't possibly have been spent on other, more worthwhile expenses like training, prisoner food, bullets and/or fuel for the constantly-idling Caprices endemic to all law enforcement.

I'm pretty sure TFA says he spends out of his own pocket.

If he, as a public servant, has that much cash to blow on a frivolous and ultimately pointless gesture, he is grossly overpaid.

You made an idiot assumption and got called out on it. Despite other people being corrected for the same assumption. Don't double down on your stupidity, just walk away.

Idiot.

/BTW Articles says that others were paid for out of his campaign funds